Solution-Synthesized High-Mobility Tellurium Nanoflakes for Short-Wave Infrared Photodetectors

Matin Amani, Chaoliang Tan, George Zhang, Chunsong Zhao, James Bullock, Xiaohui Song, Hyungjin Kim, Vivek Raj Shrestha, Yang Gao, Kenneth B. Crozier, Mary Scott, Ali Javey

Research output: Contribution to journalArticlepeer-review

171 Citations (Scopus)

Abstract

Two-dimensional (2D) materials, particularly black phosphorus (bP), have demonstrated themselves to be excellent candidates for high-performance infrared photodetectors and transistors. However, high-quality bP can be obtained only via mechanical exfoliation from high-temperature- and high-pressure-grown bulk crystals and degrades rapidly when exposed to ambient conditions. Here, we report solution-synthesized and air-stable quasi-2D tellurium (Te) nanoflakes for short-wave infrared (SWIR) photodetectors. We perform comprehensive optical characterization via polarization-resolved transmission and reflection measurements and report the absorbance and complex refractive index of Te crystals. It is found that this material is an indirect semiconductor with a band gap of 0.31 eV. From temperature-dependent electrical measurements, we confirm this band-gap value and find that 12 nm thick Te nanoflakes show high hole mobilities of 450 and 1430 cm2 V-1 s-1 at 300 and 77 K, respectively. Finally, we demonstrate that despite its indirect band gap, Te can be utilized for high-performance SWIR photodetectors by employing optical cavity substrates consisting of Au/Al2O3 to dramatically increase the absorption in the semiconductor. By changing the thickness of the Al2O3 cavity, the peak responsivity of Te photoconductors can be tuned from 1.4 μm (13 A/W) to 2.4 μm (8 A/W) with a cutoff wavelength of 3.4 μm, fully capturing the SWIR band. An optimized room-temperature specific detectivity (D∗) of 2 × 109 cm Hz1/2 W-1 is obtained at a wavelength of 1.7 μm.

Original languageEnglish
Pages (from-to)7253-7263
Number of pages11
JournalACS Nano
Volume12
Issue number7
DOIs
Publication statusPublished - 2018 Jul 24

Bibliographical note

Funding Information:
Device fabrication and measurements were supported by the Defense Advanced Research Projects Agency under contract no. HR0011-16-1-0004. Synthesis work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under contract no. DE-AC02-05CH11231 within the Electronic Materials Program (KC1201). Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Funding Information:
Device fabrication and measurements were supported by the Defense Advanced Research Projects Agency under contract no. HR0011-16-1-0004. Synthesis work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under contract no. DE-AC02-05CH11231 within the Electronic Materials Program (KC1201). Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Publisher Copyright:
© 2018 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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